1. Field of the Invention
The present invention generally relates to a circuit continuity detection system and method, and more specifically, to a circuit continuity detection system and method that senses current and voltage simultaneously at a single point of operation.
2. Description of the Related Art
In many technical applications, situations often arise where it is desirable to know, in real time, if a circuit is functioning. That is, it is desirable to know if, for example, a heater element is operational or "blown" (open). It is relatively simple to determine if the circuit is operational by sensing the current flowing to the circuit.
However, this only provides information while the circuit is in the process of operating. There must be some real-time relation to or connection with the request or demand for power, to determine if the device is in fact not operational, or if there is simply no controller request to provide power. Conventional devices provide no such means to arbitrate the presence of current in a circuit along with the voltage request or demand for power.
Furthermore, indication of a failure condition would require a continual or known interval monitor, or a connection to a controller device for continual monitoring and condition reporting. Even then, some connection with the request for power must be made to enable the proper function to be determined.
Conventional, discrete current sensing loops and voltage sensing coils could be used to derive the required parameters, and with the application of an external arbitration means, one could derive the function described. However, this method is costly, cumbersome and requires externally-powered devices. Further, its distributed nature makes it a formidable challenge to implement.
Therefore, it is necessary to assess and arbitrate the current and voltage demand at a single point to provide ease of integration. The most obvious point to obtain these parameters is at the circuit breaker that governs the operation of the circuit.
FIG. 1A illustrates a conventional circuit breaker 10 for detecting a current overload condition. Circuit power is provided from an external source 15, connected to a contact 19. The breaker includes an ON-OFF activation switch 13 which enables or disables the device's function, a current sensing coil 11, which is attached to a set of normally closed contacts 14a, 14b, and a pivot 12 that allows the actuation of contact 14a into an open state (e.g. away from its mating "closed" contact 14b) upon sensing a current overload condition. This operation "breaks" (e.g., opens) the circuit and protects the load from damage from exposure to a current above the breaker rating.
FIG. 1B illustrates a standard implementation of the circuit breaker of FIG. 1A. A voltage source 15 is connected to a voltage controller 16, which sends power to the circuit. The power is routed to one or more loads through separate circuit breakers (e.g., CB1--10a, CB2--10b). The load 18a, 18b is connected in series to its respective circuit breaker 10a, 10b.
The device of FIG. 1A, as implemented in FIG. 1B, provides the ability to open or "trip" within the series circuit to which it is installed. It has no ability to arbitrate request or demand for circuit activation, and it provides no means for external communication about its state or condition, nor about the state or condition of the circuit in which it is installed, nor about the state or condition of the load attached (e.g., 18a, 18b).